1. Field of the Invention
This invention relates to a manually propelled, carriage supported, motorized hedge trimmer, and particularly to such an apparatus wherein the operator may readily adjust the trimmer height and level while pushing the carriage beside a hedge row.
2. General Description of the Prior Art
Although motorized hedge trimmers have greatly reduced the time and effort required to trim a hedge, hedge cutting is still considered a laborous, time-consuming task. Considerable physical effort is required to manually support the conventional motorized hedge trimmer. This is especially true for trimming relatively tall and/or wide hedges. For this reason, and because of increased labor costs, many hedges have recently been destroyed. Likewise, hedges are generally much less prevalent in new neighborhoods than in old ones.
Hedge trimmers have been the subject of inventions for many years. One of the earliest of these is reflected by U.S. Pat. No. 62,487, a horsedrawn device patented in 1867. It provides means for adjustment in height, but not in tilt. Since the terrain surrounding hedges is typically uneven, the top of the hedge trimmed by this device would likewise be uneven. The device also lacked the capability to trim the sides of a hedge.
U.S. Pat. No. 1,897,543, granted in 1933, was an improvement over the previous device is that it would be manually propelled and was less complex to manufacture. Although the device could be manually adjusted in height and tilt, this adjustment could not be made while simultaneously propelling the carriage. The operator was required to stop trimming, walk around to the support shaft, loosen set screws associated with the two independent adjustments, physically support the device in the new height and/or tilt position, and manually retighten he set screws. Since the trail around a hedge is typically very uneven, many, many such adjustments would be required in trimming a hedge row for a precise, even trim.
In 1956, U.S. Pat. No. 2,762,186 was issued for a motorized hedge trimmer with a "rollable base". The device was also adjustable in height and tilt, but only after ceasing to trim the hedge, removing a pair of screws in the frame supporting the trimmers, physically readjusting the trimmer, and manually replacing the screws.
More recent patents, U.S. Pat. Nos. 3,431,647 and 3,540,122, issued in 1966 and 1970, respectively, relate to a motorized hand-held trimmer and set of spirit levels for maintaining proper level while manually supporting the trimmers. Hand-held trimmers such as these are physically tiring to support at the proper height for accurate trimming of hedges of significant lengths.
U.S. Pat. No. 3,597,908, issued in 1971, relates to a tree-trimming (or hedge trimming) cutter mounted on a forklift tractor with hydraulic means for adjusting trimmer level and depending upon the forklift for adjusting trimmer height. Such an arrangement is simply too expensive to be marketable.